Re: [f2fs-dev] [PATCH v3] f2fs: reduce expensive checkpoint trigger frequency

[Chao Yu]

On 2024/6/25 10:14, wangzijie wrote:
> > We may trigger high frequent checkpoint for below case:
> > 1. mkdir /mnt/dir1; set dir1 encrypted
> > 2. touch /mnt/file1; fsync /mnt/file1
> > 3. mkdir /mnt/dir2; set dir2 encrypted
> > 4. touch /mnt/file2; fsync /mnt/file2
> > ...
> >
> > Although, newly created dir and file are not related, due to
> > commit bbf156f7afa7 ("f2fs: fix lost xattrs of directories"), we will
> > trigger checkpoint whenever fsync() comes after a new encrypted dir
> > created.
> >
> > In order to avoid such condition, let's record an entry including
> > directory's ino into global cache when we initialize encryption policy
> > in a checkpointed directory, and then only trigger checkpoint() when
> > target file's parent has non-persisted encryption policy, for the case
> > its parent is not checkpointed, need_do_checkpoint() has cover that
> > by verifying it with f2fs_is_checkpointed_node().
> >
> > Reported-by: Zhiguo Niu <zhiguo.niu@xxxxxxxxxx>
> > Tested-by: Zhiguo Niu <zhiguo.niu@xxxxxxxxxx>
> > Reported-by: Yunlei He <heyunlei@xxxxxxxxxxx>
> > Signed-off-by: Chao Yu <chao@xxxxxxxxxx>
> > ---
> > v3:
> > - Recently, Zhiguo Niu reported the same issue, so I repost this
> > patch for comments.
> >   fs/f2fs/f2fs.h              |  2 ++
> >   fs/f2fs/file.c              |  3 +++
> >   fs/f2fs/xattr.c             | 16 ++++++++++++++--
> >   include/trace/events/f2fs.h |  3 ++-
> >   4 files changed, 21 insertions(+), 3 deletions(-)
> >
> > diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
> > index e2e0ca45f881..0094a8c85f4a 100644
> > --- a/fs/f2fs/f2fs.h
> > +++ b/fs/f2fs/f2fs.h
> > @@ -279,6 +279,7 @@ enum {
> >   	APPEND_INO,		/* for append ino list */
> >   	UPDATE_INO,		/* for update ino list */
> >   	TRANS_DIR_INO,		/* for transactions dir ino list */
> > +	ENC_DIR_INO,		/* for encrypted dir ino list */
> >   	FLUSH_INO,		/* for multiple device flushing */
> >   	MAX_INO_ENTRY,		/* max. list */
> >   };
> > @@ -1147,6 +1148,7 @@ enum cp_reason_type {
> >   	CP_FASTBOOT_MODE,
> >   	CP_SPEC_LOG_NUM,
> >   	CP_RECOVER_DIR,
> > +	CP_ENC_DIR,
> >   };
> >   
> >   enum iostat_type {
> > diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
> > index 8198afb5fb9c..18b33b1f0c83 100644
> > --- a/fs/f2fs/file.c
> > +++ b/fs/f2fs/file.c
> > @@ -218,6 +218,9 @@ static inline enum cp_reason_type need_do_checkpoint(struct inode *inode)
> >   		f2fs_exist_written_data(sbi, F2FS_I(inode)->i_pino,
> >   							TRANS_DIR_INO))
> >   		cp_reason = CP_RECOVER_DIR;
> > +	else if (f2fs_exist_written_data(sbi, F2FS_I(inode)->i_pino,
> > +							ENC_DIR_INO))
> > +		cp_reason = CP_ENC_DIR;
> >   
> >   	return cp_reason;
> >   }
> > diff --git a/fs/f2fs/xattr.c b/fs/f2fs/xattr.c
> > index f290fe9327c4..cbd1b88297fe 100644
> > --- a/fs/f2fs/xattr.c
> > +++ b/fs/f2fs/xattr.c
> > @@ -629,6 +629,7 @@ static int __f2fs_setxattr(struct inode *inode, int index,
> >   			const char *name, const void *value, size_t size,
> >   			struct page *ipage, int flags)
> >   {
> > +	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
> >   	struct f2fs_xattr_entry *here, *last;
> >   	void *base_addr, *last_base_addr;
> >   	int found, newsize;
> > @@ -772,8 +773,19 @@ static int __f2fs_setxattr(struct inode *inode, int index,
> >   	if (index == F2FS_XATTR_INDEX_ENCRYPTION &&
> >   			!strcmp(name, F2FS_XATTR_NAME_ENCRYPTION_CONTEXT))
> >   		f2fs_set_encrypted_inode(inode);
> > -	if (S_ISDIR(inode->i_mode))
> > -		set_sbi_flag(F2FS_I_SB(inode), SBI_NEED_CP);
> > +
> > +	if (S_ISDIR(inode->i_mode)) {
> > +		/*
> > +		 * In restrict mode, fsync() always tries triggering checkpoint
> > +		 * for all metadata consistency, in other mode, it only triggers
> > +		 * checkpoint when parent's encryption metadata updates.
> > +		 */
> > +		if (F2FS_OPTION(sbi).fsync_mode == FSYNC_MODE_STRICT)
> > +			set_sbi_flag(F2FS_I_SB(inode), SBI_NEED_CP);
> > +		else if (IS_ENCRYPTED(inode) &&
> > +			f2fs_is_checkpointed_node(sbi, inode->i_ino))
> > +			f2fs_add_ino_entry(sbi, inode->i_ino, ENC_DIR_INO);
> > +	}
> >   
> >   same:
> >   	if (is_inode_flag_set(inode, FI_ACL_MODE)) {
> > diff --git a/include/trace/events/f2fs.h b/include/trace/events/f2fs.h
> > index 7ed0fc430dc6..48f2e399e184 100644
> > --- a/include/trace/events/f2fs.h
> > +++ b/include/trace/events/f2fs.h
> > @@ -139,7 +139,8 @@ TRACE_DEFINE_ENUM(EX_BLOCK_AGE);
> >   		{ CP_NODE_NEED_CP,	"node needs cp" },		\
> >   		{ CP_FASTBOOT_MODE,	"fastboot mode" },		\
> >   		{ CP_SPEC_LOG_NUM,	"log type is 2" },		\
> > -		{ CP_RECOVER_DIR,	"dir needs recovery" })
> > +		{ CP_RECOVER_DIR,	"dir needs recovery" },		\
> > +		{ CP_ENC_DIR,		"persist encryption policy" })
> >   
> >   #define show_shutdown_mode(type)					\
> >   	__print_symbolic(type,						\
> > --
> > 2.40.1
>
> Hi, Chao
> I noticed the discussion about patch v2, Jaegeuk mentioned no encryption case:
> 1) parent is checkpointed
> 2) set_xattr(dir) w/ new xnid
> 3) create(file)
> 4) fsync(file)
> We will not trigger checkpoint() after this change.
> So, how about adding a rule in need_do_checkpoint? We can judge if the parent has xnid
> being checkpointed or not, if not we can still trigger checkpoint() and keep the same
> behavior before this change.

Hi wangzijie,

It may cause performance overhead to get parent's xnid by parent ino,
so I prefer to tag ENC_DIR_INO for the inode if its parent's xnid is
not checkpointed, it that fine to you?

Thanks,

> _______________________________________________
> Linux-f2fs-devel mailing list
> Linux-f2fs-devel@xxxxxxxxxxxxxxxxxxxxx
> https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel